DTIC ADA514653: Quantification of Noise Sources in EMI Surveys Technology Demonstration Report Army Research Laboratory Blossom Point Facility, Maryland July - September, 2006

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by  Defense Technical Information Center

Naval Research Laboratory
Washington, DC 20375-5320
NRL/MR/6110--10-9235
Quantification of Noise Sources in EMI Surveys
Technology Demonstration Report
Army Research Laboratory
Blossom Point, Maryland
July – September, 2006
G.R. HaRbauGH
D.a. SteinHuRSt
Nova Research, Inc.
Alexandria, Virginia
M. HowaRD
NAEVA Geophysics, Inc.
Charlottesville, Virginia
b.J. baRRow
J.t. MilleR
t.H. bell
SAIC, Inc. - ASAD
Arlington, Virginia
January 14, 2010
Approved for public release; distribution is unlimited.
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14-01-2010 Interim Report April 1, 2006 to October 8, 2008
4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER
Quantification of Noise Sources in EMI Surveys
Technology Demonstration Report 5b. GRANT NUMBER
Army Research Laboratory Blossom Point Facility, Maryland
July – September, 2006 5c. PROGRAM ELEMENT NUMBER
0603851D8Z
6. AUTHOR(S) 5d. PROJECT NUMBER
MM-0508
G.R. Harbaugh,* D.A. Steinhurst,* M. Howard,† B.J. Barrow,‡ J.T. Miller,‡ 5e. TASK NUMBER
and T.H. Bell‡
5f. WORK UNIT NUMBER
61-5802-H-9
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT
NUMBER
Naval Research Laboratory, Code 6110
4555 Overlook Avenue, SW NRL/MR/6110--10-9235
Washington, DC 20375-5320
9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR / MONITOR’S ACRONYM(S)
ESTCP
Environmental Security Technology Certification Program (ESTCP) Program Office
901 North Stuart Street, Suite 303
11. SPONSOR / MONITOR’S REPORT
Arlington, VA 22203 NUMBER(S)
12. DISTRIBUTION / AVAILABILITY STATEMENT
Approved for public release; distribution is unlimited.
13. SUPPLEMENTARY NOTES
*Nova Research, Inc., 1900 Elkin Street, Suite 230, Alexandria, VA 22308
†NAEVA Geophysics, Inc., P.O. Box 7325, Charlottesville, VA 22906
‡SAIC, Inc. - ASAD, 1225 South Clark Street, Suite 800, Arlington, VA 22202
14. ABSTRACT
This demonstration was conducted at the Army Research Laboratory Blossom Point Facility between July and September 2006. The magnitudes
and effects of several types of background and/or noise sources on the data collected with several commonly used EMI sensors were measured.
These noise sources included ground response/geology, inherent sensor noise, external noise sources, motion-induced noise, and position
uncertainty. Using Monte Carlo simulations, the impact of each noise source on the final fitted parameters result was determined. Additional
measurements were conducted at Blossom Point and other nearby locations to help separate the individual contributions of the convolved sources.
The Blossom Point site was found to provide a good benchmark for a site where it should be feasible to conduct a survey-mode EMI survey.
Two recommendations are provided as to a set of EMI sensors and a demonstration protocol to be used for future demonstrations. From these
results, we can begin to understand real world EMI survey noise sources, and quantify these effects in terms of meaningful survey configuration
parameters, such as lane spacing.
15. SUBJECT TERMS
Unexploded Ordnance (UXO) Noise sources Classification
Electromagnetic Induction (EMI) Survey background levels Discrimination
16. SECURITY CLASSIFICATION OF: 17. LIMITATION 18. NUMBER 19a. NAME OF RESPONSIBLE PERSON
OF ABSTRACT OF PAGES B.J. Spargo, NRL, Code 6110
a. REPORT b. ABSTRACT c. THIS PAGE UL 134 19b. TELEPHONE NUMBER (include area
code)
Unclassified Unclassified Unclassified [phone]
Standard Form 298 (Rev. 8-98)
i Prescribed by ANSI Std. Z39.18
Contents

Figures...........................................................................................................................................vii
Tables...........................................................................................................................................xiv
Acronyms Used.............................................................................................................................xv
1. Introduction.............................................................................................................................1
1.1 Background.........................................................................................................................1
1.2 Objectives of the Demonstration........................................................................................1
1.3 Regulatory Drivers..............................................................................................................2
1.4 Stakeholder / End User Issues.............................................................................................2
2. Technology Description..........................................................................................................2
2.1 Technology Development and Application........................................................................2
2.1.1 Geophysical Instruments.........................................................................................2
2.1.1.1 Geonics EM61 MkII...........................................................................................3
2.1.1.2 Geonics EM63....................................................................................................4
2.1.1.3 Geophex GEM-3.................................................................................................5
2.1.1.4 Position and Orientation.....................................................................................6
2.1.2 NRL Low Frequency Spectrum Analyzer..............................................................7
2.2 Data Collection and Preprocessing.....................................................................................8
2.2.1 Inherent Sensor Noise.............................................................................................8
2.2.2 Motion-Induced Noise............................................................................................8
2.2.3 External Noise.......................................................................................................10
2.2.4 Geologic Response................................................................................................12
2.2.5 Location Uncertainties..........................................................................................14
iii
2.3 Data Analysis....................................................................................................................15
2.4 Previous Testing of the Technology.................................................................................15
2.5 Factors Affecting Cost and Performance..........................................................................15
2.6 Advantages and Limitations of the Technology...............................................................16
3. Demonstration Design...........................................................................................................16
3.1 Performance Objectives....................................................................................................16
3.2 Test Site Selection.............................................................................................................17
3.2.1 Test Site History / Characteristics.........................................................................17
3.2.2 Climate..................................................................................................................18
3.2.3 Geology.................................................................................................................20
3.2.4 Test Locations within Blossom Point...................................................................21
3.2.4.1 Environmental Area..........................................................................................21
3.2.4.2 Boat Launch......................................................................................................21
3.2.4.3 L Range.............................................................................................................22
3.3 Present Operations............................................................................................................23
3.4 Pre-Demonstration Testing and Analysis.........................................................................23
3.5 Testing and Evaluation Plan.............................................................................................23
3.5.1 Demonstration Set-Up and Start-Ups...................................................................23
3.5.2 Period of Operation...............................................................................................23
3.5.3 Scope of Demonstration........................................................................................24
3.5.4 Residuals Handling...............................................................................................24
3.5.5 GPS Control Monuments......................................................................................24
3.5.6 Operational Parameters for the Technology.........................................................25
3.5.7 Demobilization......................................................................................................25
iv
3.5.8 Health and Safety Plan (HASP)............................................................................25
3.6 Characterization of the Soil by Standard Techniques.......................................................25
3.6.1 Soil Moisture.........................................................................................................25
3.6.2 Magnetic susceptibility of soils............................................................................28
3.7 Analysis of the GEM-3 Data.............................................................................................29
3.7.1 External Noise.......................................................................................................29
3.7.2 Inherent Noise.......................................................................................................32
3.7.3 Geological Response.............................................................................................35
3.7.4 Motion-Induced Noise..........................................................................................43
3.8 Analysis of the EM61 MkII Data......................................................................................71
3.8.1 Sensor Variability.................................................................................................71
3.8.2 External Noise.......................................................................................................76
3.8.3 Inherent Noise.......................................................................................................77
3.8.4 Geologic Response................................................................................................79
3.8.5 Motion-Induced Noise..........................................................................................81
3.9 Monte Carlo Study............................................................................................................94
3.9.1 Objective...............................................................................................................94
3.9.2 The Monte Carlo Approach..................................................................................94
3.9.3 System under Study..............................................................................................94
3.9.4 Stochastic Model...................................................................................................94
3.9.4.1 STEP 1. The Target is Defined.........................................................................95
3.9.4.2 STEP 2. The Survey is Defined........................................................................97
3.9.4.3 STEP 3. Synthetic Data are Created...............................................................100
3.9.4.4 STEP 4. Observed Data are Created...............................................................100
v
3.9.4.5 STEP 5. Observed Data are Inverted..............................................................101
3.9.4.6 Standard inversion..........................................................................................103
3.9.4.7 Dynamic Response Inversion.........................................................................103
3.9.5 Results.................................................................................................................104
3.10 Management and Staffing...............................................................................................108
4. Future Demonstrations........................................................................................................108
4.1 Full-Scale EMI Noise Characterization Demonstration.................................................108
4.1.1 EMI Sensors........................................................................................................109
4.1.2 Measurements.....................................................................................................111
4.1.3 Deliverables........................................................................................................111
4.2 EM61 MkII Simulation Tool Demonstration.................................................................111
4.2.1 EMI Sensors........................................................................................................111
4.2.2 Measurements.....................................................................................................112
4.2.3 Deliverables........................................................................................................112
5. Cost Assessment..................................................................................................................113
6. References...........................................................................................................................114
7. Points of Contact.................................................................................................................116
Appendix A. Health and Safety Plan....................................................................................117
Appendix B. Dipole Model Framework...............................................................................119

vi
Figures
Figure 2-1 – Geonics EM61 MkII coils on a test platform..............................................................3
Figure 2-2 – Geonics EM63 with electronics and data logger, on a test platform..........................5
Figure 2-3 – Geophex GEM-3 sensor head (40cm diameter) and electronics.................................6
Figure 2-4 – NRL Low-Frequency Spectrum Analyzer..................................................................7
Figure 2-5 – Man-portable cart........................................................................................................9
Figure 2-6 – Rail system and test tower...........................................................................................9
Figure 2-7 – MTADS EM trailer.....................................................................................................9
Figure 2-8 – Voltage time series from spectrum analyzer.............................................................10
Figure 2-9 – Relative power spectral density results from horizontal and vertical
orientation of external noise monitor.....................................................................11
Figure 2-10 – Rail system deployed at Boat Launch area, shown with Geonics EM-63 in
position...................................................................................................................12
Figure 2-11 – Data collection scheme used at individual stations on the rail system. See
text for further description.....................................................................................13
Figure 2-12 – GEM-3 ground response results for the Environmental Area.................................13
Figure 2-13 – EM63 time gate 1 response at Boat Launch............................................................14
Figure 3-1 – Location of Army Research Laboratory Blossom Point Facility..............................18
Figure 3-2 – Topographic Map of Blossom Point Research Facility, showing locations of
selected EMI Noise Test sites................................................................................19
Figure 3-3 – Climate data for LaPlata, MD...................................................................................19
Figure 3-4 – Geologic Map and Cross Section (McCartan, 1989) showing Cedar Point
Neck.......................................................................................................................20
Figure 3-5 – Environmental Area, view to the East.......................................................................21
Figure 3-6 – Boat Landing Area, view to the southwest...............................................................22
Figure 3-7 – Active Range Test Location, L-Range, view to the East..........................................23
vii
Figure 3-8 – Moisture content profiles for the Boat Launch, Environmental, and L-Range
areas.......................................................................................................................27
Figure 3-9 – Magnetic susceptibility profile for the Environmental Area.....................................28
Figure 3-10 – Magnetic susceptibility profile for the Boat Launch Area......................................28
Figure 3-11 – Magnetic susceptibility profile for the L-Range traverses......................................29
Figure 3-12 – Power Spectra Results for the GEM-3 Sensor in both Passive and Active
Monitoring Modes.................................................................................................31
Figure 3-13 – GEM-3 Static Measurements – Lower Frequencies. In-phase signals are
shown in black and quadrature signals are shown in red. The lowest white
noise level at 3930 Hz is indicated with a dotted line in the right-hand
panels.....................................................................................................................33
Figure 3-14 – GEM-3 Static Measurements – Upper Frequencies. In-phase signals are
shown in black and quadrature signals are shown in red. The lowest white
noise level at 3930 Hz is indicated with a dotted line in the right-hand
panels.....................................................................................................................34
Figure 3-15 – White Noise Levels for GEM-3 Static Measurements. Measurements at
each transmit frequency are shown as symbols (black diamonds – in-
phase, red x’s – quadrature). A polynomial fit to the data is shown as a
dashed line.............................................................................................................35
Figure 3-16 – Soil Model Response for the GEM-3 sensor. In-phase response is shown in
red and quadrature response is shown in red. The solid lines represent a
soil conductivity of 0.01 mho/m, the dashed lines 0.1 mho/m..............................36
Figure 3-17 – Soil Response for the GEM-3 at the Boat Launch Area. The experimental
data are shown as black lines and symbols. The red lines in the left-hand
panels represent model fits to each data set (measurement height). The
colored lines in the right-hand panels represent model fits at a particular
frequency as a function of measurement height....................................................38
Figure 3-18 – Soil Response for the GEM-3 at the Environmental Area. The
experimental data are shown as black lines and symbols. The red lines in
the left-hand panels represent model fits to each data set (measurement
height). The colored lines in the right-hand panels represent model fits at
a particular frequency as a function of measurement height.................................39
Figure 3-19 – Match of frequency dependent susceptibility model (red and green curves)
to measured GEM-3 soil response (black curves and symbols) at the
Environmental Area...............................................................................................41
viii
Figure 3-20 – MTADS MP Cart Motion Characterization – X,Y,Z, Pitch, and Roll. The
upper panel shows the local course-over-ground for several data sets. The
data associated with the leg color-coded red was the data source for the
following discussion..............................................................................................44
Figure 3-21 – MTADS MP Cart Motion Characterization – IMU Angular Rates and
Accelerations..........................................................................................................45
Figure 3-22 – MTADS MP Cart – GEM-3 In-phase Response. The in-phase data for the
five lowest frequencies are presented in the upper panels. The bottom
panel presents the in-phase data for the five highest frequencies (black -
2,610 Hz, red – 5,430 Hz, green – 11,430 Hz, blue – 20,010 Hz, and
magenta – 44, 370 Hz)...........................................................................................46
Figure 3-23 – MTADS MP Cart – GEM-3 Quadrature Response. The quadrature data
for the five lowest frequencies are presented in the upper panels. The
bottom panel presents the quadrature data for the five highest frequencies
(black - 2,610 Hz, red – 5,430 Hz, green – 11,430 Hz, blue – 20,010 Hz,
and magenta – 44, 370 Hz)....................................................................................47
Figure 3-24 – MTADS MP Cart – Power spectra of the GEM-3 response and the IMU
motion. An individual black line is show for each frequency in the upper
panels (see text for discussion). The acceleration and angular rate PSDs
are shown in the lower panels (X – black, Y – red, Z – green). The dotted
line in the upper panel indicates the lowest white noise level measured in
the stationary tests..................................................................................................49
Figure 3-25 – MTADS EM Trailer Motion Characterization – X,Y,Z, Pitch, and Roll.
The upper panel shows the local course-over-ground for several data sets.
The data associated with the leg color-coded red was the data source for
the following discussion........................................................................................50
Figure 3-26 – MTADS EM Trailer Motion Characterization – IMU Angular Rates and
Accelerations..........................................................................................................51
Figure 3-27 – MTADS EM Trailer Motion Characterization – GEM-3 In-phase
Response. The in-phase data for the five lowest frequencies are presented
in the upper panels. The bottom panel presents the in-phase data for the
five highest frequencies (black - 2,610 Hz, red – 5,430 Hz, green – 11,430
Hz, blue – 20,010 Hz, and magenta – 44, 370 Hz)................................................52
Figure 3-28 – MTADS EM Trailer Motion Characterization – GEM-3 Quadrature
Response. The quadrature data for the five lowest frequencies are
presented in the upper panels. The bottom panel presents the quadrature
data for the five highest frequencies (black - 2,610 Hz, red – 5,430 Hz,
green – 11,430 Hz, blue – 20,010 Hz, and magenta – 44, 370 Hz).......................53
ix
Figure 3-29 – MTADS EM Trailer Motion Characterization – Power spectra of the GEM-
3 response and the IMU. An individual black line is show for each
frequency in the upper panels. The acceleration and angular rate PSDs are
shown in the lower panels (X – black, Y – red, Z – green). The dotted line
in the upper panel indicates the lowest white noise level measured in the
stationary tests........................................................................................................54
Figure 3-30 – Tower / Rail System Motion Characterization – X,Y,Z, Pitch, and Roll...............56
Figure 3-31 – Tower / Rail System Motion Characterization – IMU Angular Rates and
Accelerations..........................................................................................................57
Figure 3-32 – Tower / Rail System Motion Characterization – GEM-3 In-phase
Response. The in-phase data for the five lowest frequencies are presented
in the upper panels. The bottom panel presents the in-phase data for the
five highest frequencies (black - 2,610 Hz, red – 5,430 Hz, green – 11,430
Hz, blue – 20,010 Hz, and magenta – 44, 370 Hz)................................................58
Figure 3-33 – Tower / Rail System Motion Characterization – GEM-3 Quadrature
Response. The quadrature data for the five lowest frequencies are
presented in the upper panels. The bottom panel presents the quadrature
data for the five highest frequencies (black - 2,610 Hz, red – 5,430 Hz,
green – 11,430 Hz, blue – 20,010 Hz, and magenta – 44, 370 Hz).......................59
Figure 3-34 – Tower / Rail System Motion Characterization – Power spectra of the GEM-
3 response and the IMU. An individual black line is show for each
frequency in the upper panels. The acceleration and angular rate PSDs are
shown in the lower panels (X – black, Y – red, Z – green). The dotted line
in the upper panel indicates the lowest white noise level measured in the
stationary tests........................................................................................................60
Figure 3-35 – GEM-3 RMS Noise (In-phase and Quadrature) by platform. The black
curves are the stationary noise levels. The curves for each site are color-
coded: Environmental – red, L Range – green, and Boat Launch – blue..............62
Figure 3-36 – IMU angular pitch rate versus the 90-Hz GEM-3 Response (In-phase and
Quadrature)............................................................................................................63
Figure 3-37 – GEM-3 Response – Measured versus IMU-based Model for Noise.
Experimental data are shown in black, modeled noise based on IMU data
is shown in red.......................................................................................................65
Figure 3-38 – GEM-3 RMS Noise Levels as a Function of Transmit Frequency. The
measured noise levels are shown as the solid lines and symbols (black –
rapid pitching, red – medium pitching, blue – slow pitching, green –
x